Electrical connectors



Oct. 11, 1960 F. RADDIN 2,956,258

ELECTRICAL CONNECTORS Filed Dec. 13, 1956 2 Sheets-Sheet 1 Il/IIIIIIIIIII I INVENTOR. FRANKLIN RADDIN AGENT Oct. 11, 1960 F. RADDIN 2,956,258

ELECTRICAL CONNECTORS Filed Dec. 1:, 1956 2 Sheets-Sheet 2 glllllllllllllllga INVENTOR. FRANKLIN RADDIN MMKM Y AGENT United States Patent ELECTRICAL CONNECTORS Franklin Raddin, Morristown, NJ., assignor to Monroe Calculating Machine Company, Orange, N.J., a corporation of Delaware Filed Dec. 13, 1956, Ser. No. 628,034

'1 Claim. (Cl. 339-45) This invention relates to electrical connectors for printed circuit cards or the like.

it is well known that printed circuit cards provide a number of advantages when used in electronic apparatus. Such cards are especially suited to mass production and make possible a reduction in the size of electronic apparatus. They also provide a modular type of construction in electronic equipments that simplifies the maintenance problem by permitting a quick substitution of small units which become defective.

To provide for easy replacement, the printed circuit cards normally include multi-contact plugs which enter into sockets in a chassis or inter-connection unit. The making of soldered connections to the ends of the plug adds to the cost of construction and such plugs have a number of disadvantages as a means for making connections to printed circuit cards, especially When the cards are miniaturized.

The plugs require an appreciable mechanical force on each pin to insure a reliable contact resistant to corrosion, vibration, and shock. As many contacts are normally required, the force necessary for insertion and removal of a card is considerable. Equipments using printed circuit cards are normally compact so that it is frequently diflicult to apply an appreciable force to remove and insert the cards.

In any event, the plugs limit the degree of miniaturization which can be obtained. The card must be large enough to withstand the forces applied to it for insertion and removal. The pin size and spacing necessary for the plug is another limiting factor on the size of the card.

The apparatus of the instant invention provides a means for making reliable connections directly to the printed terminals along the edges of printed circuit cards. The spacing of the printed terminals may be the same as the spacing of other printed conductors. Substantially zero force is required to insert and remove the cards so that they need to be only strong enough to support the printed circuitry and other circuit components.

In the apparatus of the instant invention, a fluid pressure is applied uniformly along rows of mating contacts to hold them together with suflicient force to insure connections resistant to corrosion, vibration, and shock. At least one of the-cards or -other member supporting sets of contacts is'flexible and the fluid pressure means is conformable in shape so that a substantially uniform pressure will be applied to each pair of mating contacts despite small dimensional variations in the contacts or their supporting members. The fluid pressure is removed to allow insertion and removal without wear and undesirable mechanical stress.

An object of the invention is an improved means of making connections to printed circuit cards.

A further object of the invention is apparatus for making connections directly to printed terminals on printed circuit cards wherein a uniform contact pressure is maintained with each terminal.

A still further object of this invention is apparatus Patented Oct. 11, 1960 gee for making connections to printed circuit cards from which the cards may be inserted and removed with the application of substantially zero force.

Other objects and advantages together with a fuller understanding of the invention, will be had by referring to the following description and claim taken in conjunction with the accompanying drawings in which:

Fig. l is a perspective view of one embodiment of the invention having a section cut away to show the internal structure.

Fig. 2 is an elevation view of a vertical section of the embodiment of Fig. 1 taken along the line 22.

Fig. 3 is an elevation view of a vertical section of a modification to the embodiment of Fig. l. The vertical section is taken along the line in the modification correspondent to the line 3--3 in Fig. 1.

Fig. 4 is an elevation view of a fragmentary portion of the contact assembly of the embodiment of Fig. 3.

Fig. 5 is a perspective view of a fragmentary portion of another embodiment of the invention.

Fig. 6 is a plan view of a horizontal section of the embodiment of Fig. 5 taken along the line 6-6.

Fig. 7 is an elevation view of a vertical section of the fragmentary portion of the embodiment of Fig. 5 taken along the line 7-7.

Referring now to Fig. 1 and Fig. 2, notched member 13 joins to bar 12 by screws (not shown), or by any other suitable means, so that the two form a vertical slot running longitudinally. Printed circuit card 13a is inserted in the slot from the upper side and printed circuit card 13b from the lower side so that portions thereof overlap each other in the slot. Member 11 is made of a rigid material and has a chamber hollowed out with an opening along the side of the slot. Fluid filled flexible bag 14 is mounted inside the chamber with a side adjacent to the slot. Screw 15 journeys through a threaded hole in one end of member 11 and extends inside the chamber. Plate 16 rotatably joins to the end of screw .15 inside the chamber.

When screw 15 is turned inwardly, it forces plate 16 against fluid filled bag 14. The fluid inside bag 14 is substantially incompressible so that the longitudinal compression causes the bag 14 to expand laterally into the side of the slot and to press cards 13a and 13b together against bar 12. Bag 14 is flexible so that it conforms to the shape of printed circuit card 1311 allowing pressure to be applied uniformly along the portion adjacent to the chamber opening. As the area of plate 16 is smaller than that of the portions of cards 13:; and 13b in the slot, the force exerted on the cards 13a and 13b is considerably greater than on plate 16. Screw 15 provides a further mechanical advantage for manual adjustment.

Printed circuit cards 13a and 1312 each have a plurality of printed conductors 17 extending along the overlapping sections of their adjoining sides. Printed conductors 17 on cards 13a and 1312 are in mating relation so that each conductor 17 on card 13a makes contact with a corresponding conductor 17 on card 13b when cards 13a and 13b are pressed together. Cards 13a and 13b are suificiently flexible to bend under the pressure exerted through bag 14.

This flexibility of cards 13a and 13b makes it possible to hold each mating pair of conductors 17 together with substantially the same pressure despite small dimensional irregularities in thickness. Since no close tolerances are required, cards 13a and 13b may be manufactured by low cost methods. Both cards 13a and 1311 may be of any suitable type and have any arrangement of printed circuitry and other components. One of the cards 13a or 13b may have only external circuit connectors soldered or otherwise connected to the conductors printed thereon or may additionally carry such external circuit sides adjacent to the vertical and horizontal slots.

conductors to provide for external circuit connection.

Referring now to Fig. 3 and Fig. 4, the arrangement of Fig. 1 may be modified by replacing printed circuit card 13b with the assembly consisting of -slotted member 18, rod 19, and connectors This modified arrangement is to be used in connecting a cable or other wiring to printed circuit card 13a. Replaceable jaw member 21 is also added to the arrangement shown between member 12 and card 13a and is of an insulating material so that card 13a may have conductors on both sides even though bar 12 is made of metal or other conducting material.

Slotted member 18 mounts on member 11 along the slot and is of an insulating material, such as a molded plastic or nylon. Rod 19 is also made'of an insulating material. Connectors 20 mount pivotally on rod '19 between the vertical bars of the slots of member 18. The spacing of connectors 20 is such that they are in mating relation with printed-conductors 17 on card 1311. The free ends of connectors 20' extend downwardly and alternate ones are spread apart in'a direction perpendicular to the slot to provide more space for making connections to cables or other wiring.

The dimensions'of connectors 20 perpendicular to the slot are greater than the thickness of slotted member 18 so that both edges project beyond the vertical bars of the slots of member 18. One'edge'of each connector 20 rests against fluid-filled bag 14 so that lateral expansion of bag.1'4 within the slotforces the other edge of each connector against themating conductor 17 on card 13a. Since all connectors 20 are independently supported, each will be forced against its mating conductor 17 with equal pressure. It-will be recognized that various other arrangements could be used for yieldably supporting connectors 20. Slot-ted member 18 is removable and other similar assemblies with different spacing of connectors 20 can be substituted for use with printed circuit cards 13a having different spacings of conductors 17. Jaw member 21 is also replaceable and members 21 with different dimensions may be substituted to adapt the apparatus for printed circuit cards 13a of different thickness.

Figures 5, 6, and 7 show an arrangement for connecting a number of printed circuit cards 13a to an interconnection panel 22 which may be of the printed'circuit type. This arrangement is useful in many types of electronic apparatus where a number of printed circuit cards are to be connected to a single chassis or other type of inter-connection unit.

Flat rectangular case 23 has a plurality of vertical slots into which cards 13a can be inserted and a horizontal slot adapted to receive panel 22. Flexible bag 24 is located inside case 23 and has fingers 24a extending between the'several vertical slots. Tube 25 is an extension of bag 24 and runs through a hole in case 23 to valve 26. Tube 25 provides a fluid communicating passage between valve 26 and bag 24. Valve 26 may connect tube 25 either to atmospheric pressure through a vent outlet or to pressure source'27.

Insulating member 28 having an L-shaped cross section are movably supported along each vertical slot with 'one side of the L parallel to the vertical slot and the other parallel to the horizontal slot. The movable support for members 2818 provided by rubber bushings on pins 29 which project from case 23 at each end of the vertical slots. Each member 28 has a plurality of printed conductors 17 that each have a portion on the The that used in the embodimentof Figures 1 and 2.

conductors 17 on each member 28 are in mating relation with the conductors 17 on cards 13a and panel 22.

With cards 13a and panel 22 in their respective slots, pressure is applied to bag 24 by turning valve 26 to connect tube 25 to the pressure source 27. Expansion of bag 24 forces members 28 against their respective cards 13a and against panel 22. Conductors 17 on members 28 then make contact with conductors 17 on cards 13a and panel 22 and provide the desired interconnections between cards 13a and panel 22. Members 28 are sufficiently flexible so that each pair of mating conductors 17 will be held altogether with substantially the same pressure.

In the embodiment shown, bag 24 and pressure source 27 are filled with a pneumatic fluid, such as When a card 13a or panel 22 is to be removed, the pressure exerted by bag 24 is released by turning valve 26 to connect tube 25 to the vent. When new cards 13a or panels 22 have been inserted, pressure is again applied by turning valve 26 to again connect tube 25 to pressure source 27. Pressure source 27 may be of any suitable type such as a pump and pressure tank or accumulator.

It will be recognized that bag 24-could also'be filled with an incompressible hydraulic fluid and pressure applied through a plate and screw arrangement such as It will further be recognized that various other arrangements could also be used for obtaining'fluid pressure in the several embodiments of the invention other than those shown. For example, a cam type mechanism positioned by a lever could be used instead of a screw to move a plate against the bag. Such a mechanism would permit quick application and removal of pressure but would require an additional adjusting means to obtain the desired pressure in the event of changes in dimensions of the chamber in which the bag is located or of the cards and connectors used.

While the invention has beendescribed with a certain degree of particularity, it is understood'that the present disclosure has been made only by way of example, and that numerous changes in the details of construction wherein a combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.

What is claimed is:

An electrical connector comprising a housing having a slot, a closed flexible b ag filled with a substantially incompressible fluid mounted in said housing with a first wall thereof coextensive with one side of said slot, a first conductor carrying member, comprising a slotted insulating board and electrical conductor members mounted within the slots of said board, located within said housing slot adjacent the first Wall of said bag, a second conductor carrying member adapted to fit in said housing slot with conductors thereon abutting the conductor members of said first conductor carrying member and means for exerting a force-on said bag whereby said abutting conductors are pressed together by movement of the first wall of said bag.

References Cited in the file of this patent UNITED STATES PATENTS 2,685,071 McCreary July 27, 1954 2,706,806 Templeton Apr. 19, 1955 2,730,683 Ayres et al. Jan. 10, 1956 2,827,312 Spencer Mar. 18, 1958 

